Expansion Tank empties of water

[jts46]

56 plate California comfort, AXD 5cyc. engine.

The expansion tank on my 56 plate Cali empties ,no sign of leak in engine bay or underneath with protection tray removed. It seems to empty when has been parked and when I come to it the following day.
I have had the system pressure tested, no sign of water entering engine. Has anyone else had this problem?
Could it be leaking from the rear heater? if so where is this located? Where are the pipe runs located?

I would appreciate a breakdown of the components for the rear heater if possible please.

My wife and I are planning a trip to Europe on 24th April ferry booked Newcastle/ Amsterdam travelling to and over Oresund bridge to Sweden.

 

[WelshGas]

56 plate California comfort, AXD 5cyc. engine.

The expansion tank on my 56 plate Cali empties ,no sign of leak in engine bay or underneath with protection tray removed. It seems to empty when has been parked and when I come to it the following day.
I have had the system pressure tested, no sign of water entering engine. Has anyone else had this problem?
Could it be leaking from the rear heater? if so where is this located? Where are the pipe runs located?

I would appreciate a breakdown of the components for the rear heater if possible please.

My wife and I are planning a trip to Europe on 24th April ferry booked Newcastle/ Amsterdam travelling to and over Oresund bridge to Sweden.

Click link below. Select year and then Body, I think.

Google

 

[jts46]

@WelshGas thanks for prompt reply. I can’t seem to find rear heater pipe runs.
Thank you again

 

[WelshGas]

@WelshGas thanks for prompt reply. I can’t seem to find rear heater pipe runs.
Thank you again

I think they run from engine bay down the off side to the rear Hivac unit. If you have rear AirCon as well they run from Near Side in engine bay across and down and then also down the off side under the car but above the underbody shield.

 

[Morvan Freevan]

56 plate California comfort, AXD 5cyc. engine.

The expansion tank on my 56 plate Cali empties ,no sign of leak in engine bay or underneath with protection tray removed. It seems to empty when has been parked and when I come to it the following day.
I have had the system pressure tested, no sign of water entering engine. Has anyone else had this problem?
Could it be leaking from the rear heater? if so where is this located? Where are the pipe runs located?

I would appreciate a breakdown of the components for the rear heater if possible please.

My wife and I are planning a trip to Europe on 24th April ferry booked Newcastle/ Amsterdam travelling to and over Oresund bridge to Sweden.

Although currently it is difficult to search for within the forum, there are I think a number of posts about this issue. In some it is suggested that the radiator cap might be the problem. A failed seal allowing coolant to boil away while driving and not creating sufficient vacuum to refill the tank. Is the original cap replaced during the pressure test?

 

[jts46]

Although currently it is difficult to search for within the forum, there are I think a number of posts about this issue. In some it is suggested that the radiator cap might be the problem. A failed seal allowing coolant to boil away while driving and not creating sufficient vacuum to refill the tank. Is the original cap replaced during the pressure test?

New rad cap fitted